MQTTc_SubscribeMult

Owned by Former user (Deleted)
Last updated: Jan 26, 2021 by WES Admin
2 min read

Send a 'Subscribe' message containing multiple topics to MQTT server.

Files

mqtt-c.h/mqtt-c.c

Prototype

void  MQTTc_SubscribeMult (       MQTTc_CONN   *p_conn,
                                  MQTTc_MSG    *p_msg,
                           const  CPU_CHAR    **topic_str_tbl,
                                  CPU_INT08U   *req_qos_tbl,
                                  CPU_INT08U    topic_nbr,
                                  MQTTc_ERR    *p_err);

Arguments

p_conn

Pointer to MQTTc Connection to use.

p_msg

Pointer to MQTTc Message object to use.

topic_str_tbl

Table containing string of all the topic(s) at which to subscribe. Must all stay valid until the message has been completely sent.

req_qos_tbl

Table of the requested level of QoS for each subscription.

topic_nbr

Number of topic and QoS contained in tables.

p_err

Pointer to variable that will receive the return error code from this function:

MQTTc_ERR_NONE

MQTTc_ERR_NOT_INIT

MQTTc_ERR_NULL_PTR

MQTTc_ERR_INVALID_ARG

MQTTc_ERR_INVALID_BUF_SIZE

MQTTc_ERR_FAIL

Returned Values

None.

Required Configuration

None.

Notes / Warnings

  • This function MUST be called after the µC/MQTT-client initialization has been completed.
  • Both the MQTTc_CONN object and the MQTTc_MSG object used MUST stay valid until the message has completed (callback has been called).

  • To compare with the granted QoS returned by the server with the SUBACK message, the number of topics and their QoSes are kept before the actual content to send to the server.